The first time I went to the Nether in the new snapshot, I experienced something terrible.

It just didn't load the chunks which made the other mobs not respond. That is very frustrating because I wanted to have a blaze spawner far from the nether portal. Also, the effects with what I wanted to make, didn't do what I wanted it to do.

I actually didn't check the End yet.

The Speed Block file has both resource and data.